Asia Society / Flickr

Louie Psihoyos first made waves in water and in cinematic circles in 2009 with his Academy Award-winning documentary about dolphins "The Cove." Now, the Dubuque-native is expressing his passion for protecting the Earth once again in his new film "Racing Extinction."

Kenneth Mertes

Many scientists believe that Earth is in the midst of a sixth great extinction. On this edition of Talk of Iowa, threats to biodiversity in the Midwest.

Thomas A. Bennett

At one time, the passenger pigeon was everywhere in North America.  The population was 3 to 5 billion when European settlers first arrived, but by 1914 they were gone.  Host Charity Nebbe discusses the extinction of the passenger pigeon with Stan Temple of Aldo Leopold Foundation.

Susan Groppi / Flickr

We know great herds of bison once roamed Iowa. But did you know much farther back in time there were wholly mammoths, mastodons, and even giant sloths? Host Ben Kieffer talks with ISU's Bill Clark, who'll tell us about animals that disappeared from our state with the arrival of European settlers and how some species of bears, bobcats, and cougars are coming back.